Editing Ganzfeld experiment (section)

==Analysis of results==

===Early experiments===

Between 1974 and 1982, 42 ganzfeld experiments were performed by parapsychologists.<ref name=Honorton1985/><ref name="EntangledMinds">{{cite book | title=Entangled Minds: Extrasensory Experiences in a Quantum Reality | author=Radin, Dean| publisher=Paraview Pocket Books | year=2006 | isbn=978-1416516774}}</ref> In 1982, Charles Honorton presented a paper at the annual convention of the [[Parapsychological Association]] that presented his summary of the results of the ganzfeld experiments up to that date. Honorton concluded that the results represented sufficient evidence to demonstrate the existence of psi. [[Ray Hyman]], a psychologist and noted critic of parapsychology, disagreed. Hyman criticized the ganzfeld experiment papers for not describing optimal protocols, nor including the appropriate statistical analysis. He identified three significant flaws, namely, flaws in randomization for choice of target; flaws in randomization in judging procedure; and insufficient documentation. The two men later independently analyzed the same studies, and both presented meta-analyses of them in 1985.<ref name=Honorton1985>{{cite journal | title=Meta-Analysis of Psi Ganzfeld Research: A Response to Hyman | author=Honorton, Charles | journal=Journal of Parapsychology | issue=49 | year=1985}}</ref><ref>{{cite journal | title=The Ganzfeld Psi Experiments: A Critical Appraisal |author=Hyman, Ray | author-link=Ray Hyman | journal=Journal of Parapsychology | issue=49 | year=1985}}</ref>

Hyman discovered flaws in all of the 42 ganzfeld experiments, and, to assess each experiment, he devised a set of 12 categories of flaws. Six of these concerned statistical defects, the other six "covered procedural flaws such as inadequate randomization, inadequate security, possibilities of [[sensory leakage]], and inadequate [[documentation]]."<ref name="Hyman2007">{{cite book | last=Hyman | first=Ray | author-link=Ray Hyman |chapter=Evaluating parapsychological claims | editor-last=Sternberg | editor-first=Robert J. | editor-last2=Roediger | editor-first2=Henry L. | editor-last3=Halpern | editor-first3=Diane F. | title=Critical thinking in psychology | publisher=Cambridge University Press | publication-place=Cambridge; New York | year=2007 | isbn=978-0521608343 | oclc=69423179 | pages=216–231}}</ref> Honorton himself had reported that only 36% of the studies used duplicate target sets of pictures to avoid handling cues.<ref>{{cite journal |last1=Milton |first1=Julie |last2=Wiseman |first2=Richard |author-link2=Richard Wiseman |year=2002 |title=A response to Storm and Ertel (2002) |journal=The Journal of Parapsychology |volume=66 |pages=183–186}}</ref> Over half of the studies failed to safeguard against sensory leakage and all of the studies contained at least one of the 12 flaws. After considerable back-and-forth over the relevance and importance of the flaws, Honorton came to agree with Hyman the 42 ganzfeld experiments he had included in his 1982 [[meta-analysis]] could not in themselves support the claim for the existence of [[Psi (parapsychology)|psi]].<ref name="Hyman2007" />

In 1986, Hyman and Honorton published ''A Joint Communiqué'' which agreed on the methodological problems and on ways to fix them. They suggested a computer-automated control, where randomization and the other methodological problems identified were eliminated. Hyman and Honorton agreed that replication of the studies was necessary before final conclusions could be drawn. They also agreed that more stringent standards were necessary for ganzfeld experiments, and they jointly specified what those standards should be.<ref>{{cite journal |author1=Hyman, R. |author2=Honorton, C. |year=1986 |title=A joint communiqué: the psi ganzfeld controversy |journal=Journal of Parapsychology  |volume=50 |issue=4 |pages=351–364}}</ref><ref>{{cite book | last=Neher | first=Andrew | title=The psychology of transcendence | publisher=Dover Publications | publication-place=New York | year=2011 | isbn=978-0-486-26167-6 | oclc=20562986 | page=307}}</ref>

===Autoganzfeld===
[[Image:Hyman LeeRoss DarylBem VictorBenassi.jpg|thumb|250px|right|Ray Hyman in 1983 with [[Lee Ross]], Daryl Bem and Victor Benassi]]

In 1982, Honorton had started a series of "autoganzfeld experiments", that is ganzfeld experiments controlled by a computer, at his Psychophysical Research Laboratories (PRL). The trials continued until September 1989 and in 1990 Honorton ''et al''. published the results of 11 autoganzfeld experiments they claimed met the standards specified by Hyman and Honorton (1986).<ref>{{cite journal |author1=Honorton, C. |author2=Berger, R.E. |author3=Varvoglis, M.P. |author4=Quant, M. |author5=Derr, P. |author6=Schechter, E.I. |author7=Ferrari, D.C. |year=1990 |title=Psi Communication in the Ganzfeld: Experiments with an Automated Testing System and a Comparison with a Meta-Analysis of Earlier Studies |journal=Journal of Parapsychology  |volume=54 |issue=2 |pages=99–139}}</ref> In these experiments, 240 participants contributed 329 sessions.<ref name="BemHonorton1994"/>

Hyman analyzed these experiments and wrote they met most, but not all of the "stringent standards" of the joint communiqué.<ref name="Hyman1994">{{cite journal | author = Hyman, Ray | author-link=Ray Hyman | year = 1994 | title =  Anomaly or artifact? Comments on Bem and Honorton.| journal = Psychological Bulletin | volume = 115 | issue = 1| pages = 19–24 | doi=10.1037/0033-2909.115.1.19}}</ref> He expressed concerns with the randomization procedure, the reliability of which he was not able to confirm based on the data provided by Honorton's collaborator, [[Daryl Bem]]. Hyman further noted that although the overall hit rate of 32% (7% higher than the 25% expectation from randomness) was significant, the hit rate for static targets (pictures) was, in fact, consistent with random and therefore inconsistent with Honorton's previous claims of positive results from the ganzfeld experiments that were conducted prior to 1982. The significance of the results was due entirely to a new set of "dynamic targets" (videos) that participants were able to identify at a rate that was better than random.<ref name="Hyman1994"/> In the hit rates regarding these dynamic targets, however, patterns were evident that implied visual cues were leaked:

{{quote|The most suspicious pattern was the fact that the hit rate for a given target increased with the frequency of occurrence of that target in the experiment. The hit rate for the targets that occurred only once was right at the chance expectation of 25%. For targets that appeared twice the hit rate crept up to 28%. For those that occurred three times it was 38%, and for those targets that occurred six or more times, the hit rate was 52%. Each time a videotape is played its quality can degrade. It is plausible then, that when a frequently used clip is the target for a given session, it may be physically distinguishable from the other three decoy clips that are presented to the subject for judging.<ref name="Hyman2007"/>}}

Hyman wrote these studies were an improvement over their older counterparts, but were not a successful replication of the ganzfeld experiments, nor a confirmation of psi.<ref name="Hyman1994"/> He concluded the autoganzfeld experiments were flawed because they did not preclude the possibility of [[sensory leakage]].<ref name="Hyman2007"/>

[[Richard Wiseman]] published a paper discussing a non-psi hypothesis based on possible sender to experimenter acoustic leakage in the autoganzfeld to account for the results.<ref name="Wiseman1996">{{cite journal |author1=Wiseman, R. |author2=Smith, M. |author3=Kornbrot, D. |year=1996 |title=Exploring possible sender-to-experimenter acoustic leakage in the PRL autoganzfeld experiments |journal=Journal of Parapsychology |volume=60 |pages=97–128 |issue=2  }}</ref><ref>{{cite book | last=Humphrey | first=Nicholas |author-link=Nicholas Humphrey | title=Soul searching: human nature and supernatural belief | publisher=Vintage | publication-place=London | year=1996 | isbn=978-0099273417 | oclc=36160610 | page=136 | quote=Richard Wiseman, a friend and former colleague of Honorton, has subsequently reanalysed the raw data trial by trial and shown that all the positive results can be attributed to those trials in which one or other of these sources of ‘sensory leakage’ was at least a possibility. In fact, in the relatively few trials (100 in all) where such leakage of information would not have been possible the receivers did no better than chance (26 per cent correct).}}</ref> [[David Marks (psychologist)|David Marks]] has written "Wiseman and his colleagues identified various different ways in which knowledge of the target could have been leaked to the experimenter. These included cues from the videocassette recorder and sounds from the sender who, of course, knew the target's identity... their conclusions provide little reassurance that sensory cueing of the experimenter was in any way substantially blocked."<ref name="Marks 2000"/>

Milton and Wiseman (1999) carried out a meta-analysis of ganzfeld experiments in other laboratories. They found no psi effect; the results showed no effect greater than chance from a database of 30 experiments and a non-[[Statistical significance|significant]] [[Z-test|Stouffer Z]] of 0.70.<ref name=MiltonWiseman1999>{{cite journal | title=Does Psi Exist? Lack of Replication of an Anomalous Process of Information Transfer | first1=Julie | last1=Milton | first2=Richard | last2=Wiseman |author-link2=Richard Wiseman| journal=Psychological Bulletin | year=1999 | volume= 125 | issue= 4 | pages=387–391 | doi=10.1037/0033-2909.125.4.387 | pmid=10414223 | url=http://www.richardwiseman.com/resources/ganzmeta.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.richardwiseman.com/resources/ganzmeta.pdf |archive-date=2022-10-09 |url-status=live }}</ref>

Lance Storm and Suitbert Ertel (2001) published a meta-analysis of 79 studies published between 1974 and 1996 and concluded the positive statistically significant overall outcome indicates a psi effect.<ref>{{cite journal | last1=Storm | first1=Lance | last2=Ertel | first2=Suitbert | title=Does psi exist? Comments on Milton and Wiseman's (1999) meta-analysis of Ganzfield research. | journal=Psychological Bulletin | volume=127 | issue=3 | year=2001 | doi=10.1037/0033-2909.127.3.424 | pages=424–433| pmid=11393304 }}</ref> In response, Milton and Wiseman (2001) wrote the meta-analysis of Storm and Ertel was not an accurate quantitative summary of ganzfeld research as they had included early studies which had been widely recognized as having methodological problems which make it impossible to interpret the results as evidence of a psi effect.<ref name=MiltonWiseman2001>{{cite journal | title=Does psi exist? Reply to Storm and Ertel (2001) | first1=Julie | last1=Milton | first2=Richard | last2=Wiseman |author-link2= Richard Wiseman| journal=Psychological Bulletin | year=2001 | volume= 127 | issue= 3 | pages=434–438 | doi=10.1037/0033-2909.127.3.434 | citeseerx=10.1.1.377.1535 }}</ref>

Another meta-analysis was conducted by Daryl Bem, John Palmer, and Richard Broughton in which the experiments were sorted according to how closely they adhered to a pre-existing description of the ganzfeld procedure including some experiments that had been published in the time since Milton and Wiseman's deadline. They obtained results that were significant with a Stouffer Z of 2.59, but their detractors maintained their selection of studies for inclusion was problematic.<ref name=BemEtAl2001>{{cite journal|title=Updating the ganzfeld database: A victim of its own success? |vauthors=Bem DJ, Palmer J, Broughton RS |journal=Journal of Parapsychology |volume=65 |issue=3 |date=September 2001 |pages=207–218 |url=http://instruct1.cit.cornell.edu/courses/psych113/Bemetal.pdf |url-status=dead |archive-url=https://web.archive.org/web/20060914123724/http://instruct1.cit.cornell.edu/courses/psych113/Bemetal.pdf |archive-date=2006-09-14 }}</ref><ref>{{cite book | last1=Alcock | first1=James |author-link=James Alcock |last2=Burns |first2=Jean |last3=Freeman |first3=Anthony | title=Psi wars: getting to grips with the paranormal | publisher=Imprint Academic | publication-place=Exeter, UK/Charlottesville, VA | year=2003 | isbn=0907845487 | oclc=53963000 | page=59}}</ref>

===Contemporary research===
The ganzfeld experiment has continued to be refined over the years. In its current incarnation, an automated computer system is used to select and display the targets ("digital autoganzfeld"). This has the potential to overcome some of the shortcomings of earlier experimental setups, such as randomization and experimenter blindness with respect to the targets.<ref name=GouldingEtAl2004>{{cite journal | author1=Goulding, A. |author2=Westerlund, J. |author3=Parker, A. |author4=Wackermann, J. | year=2004 | title=The first Digital Autoganzfeld study using a real-time judging procedure | url=https://www.academia.edu/download/30657773/EJP_v19.pdf#page=69 |archive-url=https://ghostarchive.org/archive/20221009/https://www.academia.edu/download/30657773/EJP_v19.pdf#page=69 |archive-date=2022-10-09 |url-status=live | journal=European Journal of Parapsychology | volume=19 | pages=66–97}}{{dead link|date=July 2022|bot=medic}}{{cbignore|bot=medic}}</ref>

In 2010, Lance Storm, Patrizio Tressoldi, and Lorenzo Di Risio analyzed 29 ganzfeld studies from 1997 to 2008. Of the 1,498 trials, 483 produced hits, corresponding to a hit rate of 32.2%. This hit rate is [[Statistical significance|statistically significant]] with p < .001. Participants selected for personality traits and personal characteristics thought to be psi-conducive were found to perform significantly better than unselected participants in the ganzfeld condition.<ref name=StormEtAl2010>{{cite journal | last1=Storm | first1=Lance | last2=Tressoldi | first2=Patrizio E. | last3=Di Risio | first3=Lorenzo | title=Meta-analysis of free-response studies, 1992–2008: Assessing the noise reduction model in parapsychology | journal=Psychological Bulletin | volume=136 | issue=4 | year=2010 | doi=10.1037/a0019457 | pages=471–485 | url-status=dead | archive-url=https://web.archive.org/web/20110124055506/http://www.psy.unipd.it/~tressold/cmssimple/uploads/includes/MetaFreeResp010.pdf | archive-date=2011-01-24 | access-date=2010-08-18 | pmid=20565164 | url=http://www.psy.unipd.it/~tressold/cmssimple/uploads/includes/MetaFreeResp010.pdf }}</ref> Hyman (2010) published a rebuttal to Storm ''et al''. concluding that the ganzfeld studies have not been independently replicated and had thus failed to produce evidence for psi.<ref>{{cite journal|author=Hyman R.|author-link=Ray Hyman|year=2010|title=Meta-analysis that conceals more than it reveals: Comment on Storm et al. (2010) |journal=Psychological Bulletin|volume=136|issue=4|pages=486–490|doi=10.1037/a0019676|pmid=20565165 | url = http://drsmorey.org/bibtex/upload/Hyman:2010.pdf | url-status = dead | archive-url = https://web.archive.org/web/20131103081111/http://drsmorey.org/bibtex/upload/Hyman%3A2010.pdf | archive-date = 2013-11-03 }}</ref> According to Hyman, "reliance on meta-analysis as the sole basis for justifying the claim that an anomaly exists and that the evidence for it is consistent and replicable is fallacious. It distorts what scientists mean by confirmatory evidence." Storm ''et al''. published a response to Hyman claiming the ganzfeld experimental design has proved to be consistent and reliable but parapsychology is a struggling discipline that has not received much attention so further research on the subject is necessary.<ref>{{cite journal | last1=Storm | first1=Lance | last2=Tressoldi | first2=Patrizio E. | last3=Risio | first3=Lorenzo Di | title=A meta-analysis with nothing to hide: Reply to Hyman (2010). | journal=Psychological Bulletin | volume=136 | issue=4 | year=2010 | doi=10.1037/a0019840 | pages=491–494 | s2cid=21103309 | pmid=20565166 }}</ref> Rouder ''et al''. in 2013 wrote that critical evaluation of Storm ''et al''.'s meta-analysis reveals no evidence for psi, no plausible mechanism, and omitted replication failures.<ref>{{cite journal | last1=Rouder | first1=Jeffrey N. | last2=Morey | first2=Richard D. | last3=Province | first3=Jordan M. | title=A Bayes factor meta-analysis of recent extrasensory perception experiments: Comment on Storm, Tressoldi, and Di Risio (2010). | journal=Psychological Bulletin | volume=139 | issue=1 | year=2013 | doi=10.1037/a0029008 | pages=241–247 | pmid=23294092 }}</ref>

A 2016 paper examined questionable research practices in the ganzfeld experiments and simulated how such practices could cause erroneous positive results.<ref>{{cite journal|title=Testing for Questionable Research Practices in a Meta-Analysis: An Example from Experimental Parapsychology|last1=Bierman|first1=DJ|last2=Spottiswoode|first2=JP|last3=Bijl|first3=A|year=2016|journal=PLOS ONE|volume=11|issue=5|page=1|doi=10.1371/journal.pone.0153049|quote=We consider [questionable research practices] in the context of a meta-analysis database of Ganzfeld–telepathy experiments from the field of experimental parapsychology. The Ganzfeld database is particularly suitable for this study, because the parapsychological phenomenon it investigates is widely believed to be nonexistent.|pmid=27144889|pmc=4856278|bibcode=2016PLoSO..1153049B|doi-access=free}}</ref>